Poly(methyl methacrylate) (PMMA) nanocomposites containing well-dispersed multiwalled carbon nanotubes (MWNTs) were prepared via an in-situ bulk polymerization of methyl methacrylate (MMA) in the presence of carbon nanotubes (CNTs). Electrical conductivities of the synthesized PMMA/ MWNT nanocomposite films containing 1-5 wt % of MWNT were between 10 -4 and 10 -2 S/cm. When PMMA/MWNT nanocomposites with the same MWNT concentrations were electrospun in DMF into nanofibrous membrane, the conductivities were reduced to ∼10 -10 S/cm, even though dispersion of the MWNTs in the electrospun nanofibers was superior to the conventional polymer composites with carbon nanotubes. The diameter of the electrospun fibers ranged between 120 ( 30 and 710 ( 20 nm. In addition, MWNTs in the electrospun nanofibers were found to be embedded in the polymer matix and to align along the fiber axis.

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Abstract. This study developed a streamflow drought severity-duration-frequency (SDF) curve that is analogous to the well-known depth-duration-frequency (DDF) curve used for rainfall. Severity was defined as the total water deficit volume to target threshold for a given drought duration. Furthermore, this study compared the SDF curves of four threshold level methods: fixed, monthly, daily, and desired yield for water use. The fixed threshold level in this study is the 70th percentile value (Q 70 ) of the flow duration curve (FDC), which is compiled using all available daily streamflows. The monthly threshold level is the monthly varying Q 70 values of the monthly FDC. The daily variable threshold is Q 70 of the FDC that was obtained from the antecedent 365 daily streamflows. The desired-yield threshold that was determined by the central government consists of domestic, industrial, and agricultural water uses and environmental in-stream flow. As a result, the durations and severities from the desired-yield threshold level were completely different from those for the fixed, monthly and daily levels. In other words, the desired-yield threshold can identify streamflow droughts using the total water deficit to the hydrological and socioeconomic targets, whereas the fixed, monthly, and daily streamflow thresholds derive the deficiencies or anomalies from the average of the historical streamflow. Based on individual frequency analyses, the SDF curves for four thresholds were developed to quantify the relation among the severities, durations, and frequencies. The SDF curves from the fixed, daily, and monthly thresholds have comparatively short durations because the annual maximum durations vary from 30 to 96 days, whereas those from the desired-yield threshold have much longer durations of up to 270 days. For the additional analysis, the return-period-duration curve was also derived to quantify the extent of the drought duration. These curves can be an effective tool to identify streamflow droughts using severities, durations, and frequencies.

Abstract— Local‐dimming backlight techniques can significantly improve the static contrast and power consumption of LCD panels. Several local‐dimming backlight systems have been previously reported. However, there is currently no comprehensive description regarding the evaluation of such systems. This paper proposes some methods for evaluating the power consumption, brightness, and contrast performance of local‐dimming backlight systems and discusses the general artifacts affecting the image quality for these systems.

The particle/polymer/solvent suspension system shows complicated microstructure. When the suspension system experiences an industrial process such as coating and drying, the system experiences microstructural change. In this study, we investigated the microstructural change during the drying of a silica/polyvinyl alcohol (PVA) suspension, with an emphasis on suspension stability. We controlled the amount of PVA adsorption on the silica surface by adjusting the pH (1.5, 3.6, and 9) of the silica/PVA suspension. The amount of adsorption was measured to increase with decreasing pH, and the degree of flocculation in the silica/PVA suspension became stronger with decreasing pH. However, through the measurement of stress development during drying and the observation of film microstructure after drying, we found that the more strongly flocculated suspension became a more disperse, close-packed film after drying. By evaluating the potential energy, we could suggest the role of adsorbed polymers in structural change during the drying of the silica/PVA suspension. As pH decreases, the adsorbed polymers could bridge the particles and lead to a flocculated suspension before drying. As the solvent evaporates during drying, the adsorbed polymers introduce steric repulsion between approaching particles, leading to a change from flocculated to dispersed microstructure. This implies that the required silica/PVA film performance and the microstructure of the silica/PVA suspension can be tailored through controlling the polymer adsorption in suspension.

This study developed a methodological framework to update the rainfall intensity-duration-frequency (IDF) curves under climate change scenarios. A model output statistics (MOS) method is used to downscale the daily rainfall of general circulation models (GCMs), and an artificial neural network (ANN) is employed for the disaggregation of projected daily rainfall to hourly maximum rainfall, which is then used for the development of IDF curves. Finally, the 1st quartiles, medians, and 3rd quartiles of projected rainfall intensities are estimated for developing IDF curves with uncertainty level. Eight GCM simulations under two radiative concentration pathways (RCP) scenarios, namely, RCP 4.5 and RCP 8.5, are used in the proposed framework for the projection of IDF curves with related uncertainties for peninsular Malaysia. The projection of rainfall revealed an increase in the annual average rainfall throughout the present century. The comparison of the projected IDF curves for the period 2006–2099 with that obtained using GCM hindcasts for the based period (1971–2005) revealed an increase in rainfall intensity for shorter durations and a decrease for longer durations. The uncertainty in rainfall intensity for different return periods for shorter duration is found to be 2 to 6 times more compared to longer duration rainfall, which indicates that a large increase in rainfall intensity for short durations projected by GCMs is highly uncertain for peninsular Malaysia. The IDF curves developed in this study can be used for the planning of climate resilient urban water storm water management infrastructure in Peninsular Malaysia.

Highly substituted potato starch phosphate (HPSP) particles were synthesized via an esterification process of potato starch with a mixture of several different concentrations of disodium hydrogen phosphate and sodium hydrogen phosphate. These particles were characterized via thermogravimetric analysis, scanning electron microscope, and inductively coupled plasma mass spectrometer. The electrorheological (ER) fluid was prepared by dispersing these HPSP particles in nonconducting silicone oil, and their ER properties were investigated. The HPSP particle-based ER fluid exhibited typical ER responses with a nonzero yield stress under an applied electric field. We examined the yield stresses for the potato starch-based anhydrous ER system by varying the degree of phosphate substitution and found that the higher polarization induced by the external electric field strength resulted in the higher values of yield stresses and shear stresses.

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